In general, the patients suffering from coronary artery obstructive disease ("CAOD"), accompany stenosis of coronary arteries or peripheral blood vessels caused by atheromatous plaques, which may result in decrease in blood flow rate, angina or even sudden death.
Treatment for the patients with CAOD includes the following methods: First, bypass surgery which aims to artificially maintain the blood flow via graft vessel has been introduced in the art. However, it accompanies severe pain at incision site and fear of the patient. Secondly, balloon catheter-using method has been suggested, which comprises a step of inserting a fine balloon catheter into narrowed blood vessel, fixing it at the constricted region and expanding the balloon to broaden the constricted region. Although this method solved the shortcomings of angioplasty to some extent, a problem still remains unsolved that restenosis rate is over 70%. Thirdly, a meshed metallic stent-using method, which comprises a step of inserting the meshed stainless-steel stent into a constricted blood vessel to expand the blood vessel to the normal width and recover normal flow rate of blood. This method slightly decreased restenosis which was observed in the said balloon catheter method, however, the said limitations of the conventional methods, e.g., pain and high restenosis rate, remained unsolved. Moreover, poor flexibility of the metallic stent raised a new problem that it is very difficult to apply the stent to a curved vessel.